This invention relates to improved methods and apparatus for processing workpieces, more particularly, processing workpieces for electronic device fabrication.
The successful processing of materials for electronic devices typically requires optimization and precise control of the processing environment at all process steps. Many of these process steps are performed under conditions that make it difficult or impossible to measure the desired process variables. In those cases where an important process variable cannot be readily measured (e.g. semiconductor wafer temperature during a plasma etch step for an integrated circuit), an attempt is made to correlate the parameter of interest to other measurable or controllable parameters. The accuracy and stability of these correlations, also called equipment response models, are a critical factor in determining the process capability and device yield at any given process step.
An accurate equipment response model for a given process step will typically have both spatial (dependence upon location within the process tool) and temporal (dependence upon process time or sequence) components. In applications such as semiconductor wafer processing, the industry trend toward larger wafers makes it increasingly important that not only the average values but also the distribution and uniformity of critical process parameters be measured. This spatial mapping requirement usually requires distribution of multiple sensors within the processing area; consequently, there may be increased probability of process perturbation and reduced response model quality. Obtaining process time dependent data typically requires in-situ and substantially real time instrumentation and measurement. These measurement techniques often have requirements (e.g. optical access, electrical connections, etc.) that are incompatible with or intrusive to the processing environment and tool configuration.
Obtaining or verifying an equipment response model under these conditions can be difficult, expensive, and problematic. The introduction of potentially perturbing sensor elements and their associated feedthroughs and connections into the process environment (e.g. thermocouples into a plasma discharge) is undertaken with great reluctance. Therefore, most of the intrusive applications are only used by equipment developers and, to a lesser extent, high-end process developers. Even though such applications will clearly benefit high volume production, advance instrumentation and modeling is almost never used in such environments. This is because the danger of process perturbation usually exceeds the potential benefits.
Equipment response models are often highly sensitive to specific process parameters, sometimes in ways that are not readily apparent. For example, in a typical plasma etch system the wafer temperature can be dependent upon the process gas mix and wafer backside roughness as well as the more obvious parameters of chuck temperature, RF power, and backside helium pressure. Equipment response models developed with an incomplete understanding of all interactions or that are made under conditions significantly different from the actual manufacturing conditions can have serious errors. It is unlikely that one could adequately anticipate the final optimum processing conditions and wafer states so as to produce a generally acceptable response model; this is particularly true during the design and development stage when measurements for response models are typically made.
Equipment response models can be highly sensitive to hardware variations such as surface finish on an electrostatic chuck used in semiconductor wafer processing. An attempt to stabilize a response model by specifying tight tolerances on numerous attributes of a component is usually costly and ineffective. Important hardware attributes often undergo a slow change over time, and these changes may be reflected as drift in the form of slowly increasing inaccuracy in the equipment response model.
Clearly, there are numerous applications requiring reliable and efficient methods and apparatus by which spatially resolved and time resolved equipment response models can be easily and economically developed and maintained. An example of an important application is the uniform processing of workpieces such as semiconductor wafers, flatpanel displays, and other electronic devices. Furthermore, there is a need for methods and apparatus capable of collecting data for response models in a nonperturbing manner on unmodified process equipment running realistic process conditions. Still further, there is a need for methods and apparatus capable of generating, checking, and frequently updating response models for individual pieces of equipment in a manufacturing facility so as to improve the operating efficiency, improve the productivity, and reduce the cost of ownership for the equipment and for the overall manufacturing facility.
This invention seeks to provide methods and apparatus that can improve the performance and productivity of processes and process tools used for processing workpieces. One aspect of the present invention includes methods of acquiring data for generating response models and for monitoring, controlling, and optimizing processes and process tools. The method is carried out using a sensor apparatus that has information processing capabilities. The method includes the step of loading the sensor apparatus into the process tool and measuring the operating characteristics with the sensor apparatus. The method further includes converting the measured operating characteristics into digital data using the sensor apparatus. In addition, the method includes performing at least one step of storing the digital data in the sensor apparatus and transmitting the digital data to a receiver.
Another aspect of the present invention is an apparatus for acquiring data for monitoring, controlling, and optimizing processes and process tools. The apparatus includes a substrate and at least one sensor supported by the substrate. An information processor having information processing capability is supported by the substrate. The information processor is connected with the sensor so that information from the sensor can be provided to information processor. An internal communicator is supported by the substrate. The internal communicator is connected with the information processor so that the information processor can provide information to the internal communicator. The internal communicator is capable of transmitting information received from the information processor. A power source is supported by the substrate. The power source is connected so as to provide power to at least one of: the information processor, the internal communicator, and the sensor.
In a further embodiment of the apparatus, the internal communicator is capable of using wireless communication techniques for transmitting information to a receiver.
Optionally, the internal communicator is capable of bi-directional communication.
In a still further embodiment, the information processor may have data storage capability for storing measured data, storing operational data, storing calibration data, and other information. Optionally, the information processor may also have capabilities for mathematically manipulating the measured data.
Another aspect of the present invention includes a method of operating a sensor apparatus for acquiring data for monitoring, controlling, and optimizing processes and process tools. In an example embodiment, the method includes a program that is executable by the sensor apparatus. The method includes the step of initializing the sensor apparatus so that the sensor apparatus is ready for collecting and processing data. The method also includes the step of causing the sensor apparatus to do at least one step of: collecting and processing data, sending data to a receiver, storing data, and executing an operational command. The method may include, after the initializing step, the step of causing the sensor apparatus to enter a sleep mode for the purpose of reducing power use.
Still, another aspect of the present invention includes a method of operating a manufacturing facility for processing workpieces. The method includes the step of providing at least one process tool capable of processing workpieces. The method also includes the step of providing a sensor apparatus capable of wirelessly collecting process data. The sensor apparatus is capable of at least one of
1. wirelessly transmitting process data from within the process tool and
2. storing process data while in the process tool. In addition, the sensor apparatus is also capable of being loaded into and unloaded from the process tool without substantially interrupting the operation of the process tool. The method also includes the step of measuring process data for operation of the process tool using the sensor apparatus. The method further includes performing at least one step of monitoring the performance of the process tool using data from the sensor apparatus and maintaining the performance of the process tool in response to process data measured with the sensor apparatus.
It is to be understood that the invention is not limited in its application to the details of construction and to the arrangements of the components set forth in the following description or illustrated in the drawings. The invention is capable of other embodiments and of being practiced and carried out in various ways. In addition, it is to be understood that the phraseology and terminology employed herein are for the purpose of description and should not be regarded as limiting.
As such, those skilled in the art will appreciate that the conception, upon which this disclosure is based, may readily be utilized as a basis for the designing of other structures, methods and systems for carrying out aspects of the present invention. It is important, therefore, that the claims be regarded as including such equivalent constructions insofar as they do not depart from the spirit and scope of the present invention.
Further, the purpose of the foregoing abstract is to enable the U.S. Patent and Trademark Office and the public generally, and especially the scientists, engineers and practitioners in the art who are not familiar with patent or legal terms or phraseology, to determine quickly from a cursory inspection the nature and essence of the technical disclosure of the application. The abstract is not intended to define the invention of the application, which is measured by the claims, nor is the abstract intended to be limiting as to the scope of the invention in any way.